Human papillomavirus (HPV) is a small DNA virus infectious to human beings which belongs to papovaviridae and is classified into various types based on base sequences of DNA thereof. Hitherto, there have been isolated and identified more than 50 types of HPV from HPV-infected tissues.
HPV infection causes a variety of diseases such as verruca vulgaris, verruca plana, myrmecia, epidermodysplasia verruciformis, condyloma acuminatum, laryngenal papillomatosis, etc. which are distinguished depending on regions of human the body at which the symptom appears, and features on shapes and tissue images thereof. Since some of these diseases become malignant and are turned into cervical cancer, squamous carcinoma and the like, a great attention has focused on the early diagnosis of HPV infectious disease. The HPV infectious disease mentioned herein is meant to include not only the various above mentioned diseases induced by the HPV infection but also conditions where HPV is carried by individuals without outbreak of disease.
HPV infection can be diagnosed by detecting an antigen-antibody reaction between an antigen in epidermal tissues taken from individuals suspected of the infection and an anti-HPV antibody.
In diagnosis of HPV infection utilizing the anti-HPV antibody, it is preferable to firstly diagnose whether there is any HPV infection by utilizing an antibody capable of reacting with various types of HPV (primary diagnosis) and then to determine the type of infecting HPV with a type-specific antibody which reacts only with a specific type of HPV (secondary diagnosis). A diagnosis utilizing only the type-specific antibody without primary diagnosis requires a large number of type-specific antibodies and wastes much time and labor since the diagnosis with the type-specific antibody requires all of more than 50 type-specific antibodies and a large amount of epidermal tissues necessary for diagnosis using each type-specific antibody.
Among known antibodies capable of reacting with various papillomaviruses (hereinafter referred to as "PV") is a rabbit anti-bovine papillomavirus (hereinafter referred to as "BPV") antibody which is a known reagent commercially available from DAKO CO. (catalogue No. B580). This antibody is obtained by immunizing a rabbit with a chemically treated bovine papillomavirus type 1 (hereinafter referred to as "BPV-1") and it has been evaluated to be capable of reacting with any of a wide variety of PVs not only BPV-1. However, the present inventors have tested this antibody for its reactivity with a variety of PVs and have found that this antibody could not detect some HPV infectious diseases as will be shown in the Experiment described hereinafter.
Another known antibody reactive with a variety of HPV is an anti-HPV antibody produced by immunizing a rabbit with a sodium dodecyl sulfate (hereinafter referred to as "SDS")-disrupted HPV (JNCI Vol. 64, pp495-500, 1980). However, it is necessary to steadily provide a large amount of HPV as an antigen for producing this antibody steadily but HPV grows only in human body and a method has not yet been established for growth of HPV in tissue culture and the like, and hence, this antibody is disadvantageous to an industrial, steady production in a large amount.
It is known that a monoclonal antibody, which is produced by forming a hybridoma of an antibody-producing cell and a cell capable of rapidly and semi-permanently proliferating such as myeloma cell, followed by culture of said hybridoma, is more advantageous than a polyclonal antibody from various points of view.
A production of an anti-HPV monoclonal antibody by a hybridoma is disclosed in European Patent Publication No. 174228A and Roseto A. et al. (J. Gen. Virol. Vol. 65, pp 1319-1324, 1984). The anti-HPV monoclonal antibodies disclosed in these references are, however, type-specific antibodies capable of reacting only with human papilloma-virus type 1 (HPV-1) and not those reactive with various other HPVs. According to the description of the literature, Western blotting of the monoclonal antibodies revealed that they reacted with 54 kilodaltons and 76 kilodaltons of polypeptides in the protein component of HPV-1.
U.S. Pat. No. 4,551,270 and PCT Application WO 8605816A also disclose an amino acid sequence of a short peptide which can be a common antigen of various HPVs and describe that a monoclonal antibody capable of reacting with various HPVs can be prepared by utilizing the peptide as an antigen. However, an anti-HPV monoclonal antibody capable of reacting with various HPVs is not actually obtained in these references.
Lex M. Cowsert et al. (JNCI, Vol. 79, No. 5, pp1053-1057, Nov. 1987) also report a monoclonal antibody produced by immunizing a mouse with an SDS-treated bovine PV; and Orth G. et al. (Virology No 1. 91, pp243-255, 1978) disclose a polyclonal antibody produced by immunizing a guinea pig with an alkali-treated HPV, said polyclonal antibody being genus specific, not type-species specific.
A novel monoclonal antibody capable of reacting with a variety of HPVs and a novel process for preparing said monoclonal antibody are still earnestly desired in the field.